Biomedical subjects

Y Yano

Publications and source records attributed to Y Yano.

At least 163 records · Page 9Linked to original sources

PubMed1997

Distribution of polyunsaturated Fatty acids in bacteria present in intestines of deep-sea fish and shallow-sea poikilothermic animals.

The lipid and fatty acid compositions in nine obligate and facultative barophilic bacteria isolated from the intestinal contents of seven deep-sea fish were determined. Phospholipid compositions were simple, with phosphatidylethanolamine and phosphatidylglycerol predominating in all strains. Docosahexaenoic acid (DHA; 22:6n-3), which has not been reported in procaryotes except for deep-sea bacteria, was found to be present in eight strains at a level of 8.1 to 21.5% of total fatty acids. In the other strain, eicosapentaenoic acid (EPA; 20:5n-3) was present at a level of 31.5% of total fatty acids. Other fatty acids observed in all strains were typical of marine gram-negative bacteria. Subcultures from pouches prepared from intestinal contents of five deep-sea fish by the most-probable-number (MPN) method were analyzed for fatty acids, and all subcultures contained DHA and/or EPA. Accordingly, viable cell counts of bacteria containing DHA and EPA were estimated at a maximum of 1.3 x 10(sup8) and 2.4 x 10(sup8) cells per ml, respectively, and accounted for 14 and 30%, respectively, of the total cell counts in the intestinal contents of the deep-sea fish. In the case of 10 shallow-sea poikilothermic animals having bacterial populations of 1.1 x 10(sup6) to 1.9 x 10(sup9) CFU per ml in intestinal contents, no DHA was found in the 112 isolates examined, while production of EPA was found in 40 isolates from cold- and temperate-sea samples. These results suggest that DHA and EPA are involved in some adaptations of bacteria to low temperature and high pressure.

Journal Article↗

PubMed1997

Photochemically induced colonic ischaemic lesions: a new model of ischaemic colitis in rats.

BACKGROUND: Recent clinical studies suggest that ischaemic colitis is caused by a microcirculatory disturbance that involves thrombosis of the colon. AIM: To establish a new model of photochemically induced ischaemic colitis in rats. METHODS: Thirty male Wistar rats were anaesthetised with amobarbital, the femoral veins were cannulated and laparotomies were performed. The serosal surface of the proximal colon was irradiated by using a krypton laser (wavelength 568 nm, 20 mW) for four minutes. An intravenous infusion of a photosensitising dye, rose bengal (20 mg/kg body weight), was administered over 90 seconds, beginning at the start of irradiation. Rats were killed immediately (n = 4), 12 hours (n = 2), 24 hours (n = 10), three days (n = 4), seven days (n = 4), 14 days (n = 2), or 28 days (n = 2) after irradiation. Two control rats received laser irradiation without dye infusion. Specimens of the irradiated sites were examined by using histopathology. RESULTS: Localised ulcers of the colon were present in rats killed at 12 hours, 24 hours, three days, and seven days after irradiation. Microscopy findings were consistent with the features of human ischaemic colitis. Reproducible ulcerative lesions were produced by photothrombosis of microvessels in the colon. CONCLUSION: This model may be useful for further investigation of the pathophysiology of ischaemic colitis.

Animals↗

PubMed1997

Abnormal metabolism of type-IV collagen in normotensive non-insulin-dependent diabetes mellitus patients.

The objective of this study was to investigate the serum level of the 7S domains of type-IV collagen [IVc(7S)] and its relations with microangiopathy in non-insulin-dependent diabetes mellitus (NIDDM). This study comprised 73 patients with NIDDM that were consulted in our outpatient clinic. Among the 73 NIDDM patients, 43 with normal arterial pressure were selected to assess the relationship between serum levels of 7S collagen and microangiopathy. There was a significant relationship between the serum IVc(7S) levels and the presence of retinopathy and nephropathy. These findings suggest that an increased IVc (7S) concentration may reflect the abnormal collagen metabolism of the vascular basement membrane in NIDDM patients. Column chromatography of the NIDDM patients' sera revealed the heterogeneity of immunoreactive type-IV collagen (7S) and showed that these domains were composed mainly of degradation products of type-IV collagen. These data suggest that degradation of IVc is accelerated in the vascular basement membrane of NIDDM patients.

Chromatography↗

PubMed1997

Immunolocalization of lipoprotein(a) in wounded tissues.

Fifty samples from inflamed tissues were examined by immunohistochemical techniques, using antibodies against apo(a), apo B, plasminogen, fibrinogen, proliferating cell nuclear antigen (PCNA), and various components of extracellular matrix. The immunohistochemical features of granulation tissues were characterized by different stages of wound healing. In the first stage, immunoreactivities for anti-apo(a) and anti-apo B were weak and focal, whereas those for anti-plasminogen and anti-fibrinogen were strong and were widespread on the tissue surface. In the second stage, granulation tissues were covered with loose fibrous connective tissue, designated as a "fibrous cap." In this stage, markedly positive staining for lipoprotein(a) [Lp(a)] was observed closer to the surface of the fibrous cap than plasminogen, suggesting that Lp(a) may prevent external fibrinolysis. Lp(a) was also found in endothelial cells and the extracellular space of small vessels underlying the fibrous cap. In the last stage of healing, apo(a) and apo B were not detectable in completely organized tissues. These findings suggest that Lp(a) plays a role in the wound healing.

Apolipoproteins B↗

PubMed1997

The inhibitory effect of vitamin E on arachidonic acid metabolism during the process of urethane-induced lung tumorigenesis in mice.

It is known that change in the arachidonic acid metabolism plays an important role in the development of tumors. This study was undertaken to understand the relationship of changes in lipoxygenase, cyclooxygenase and ornithine decarboxylase (ODC) to the inhibitory effect of vitamin E on urethane-induced lung tumorigenesis in mice. We analyzed the inhibitory effect of vitamin E on ornithine decarboxylase, cyclooxygenase and lipoxygenase activities at a promotion phase of lung tumorigenesis in mice. An increase in the ODC of urethane treated-mice and no significant change in the ODC of VE-treated mice were observed. An increase in the production of PGE2 and all HETES tested in the lungs of the urethane-treated mice was observed at week 8 after injection (promotion phase), showing a significant difference compared to the control group. Excessive vitamin E feeding during the initiation or promotion phases inhibited the increase in PGE2 and HETES produced by urethane treatment. These results suggest that the suppression of prostagrandin metabolism and ODC may be associated with the inhibitory effect of vitamin E against urethane-induced lung tumorigenesis.

Animals↗

PubMed1997

Gender differences in effects of 20 days horizontal bed rest on muscle strength in young subjects.

Gender differences in the effect of 20 days bed rest (BR) on muscle strength were evaluated in voluntary 11 male and 7 female students. Maximum Isometric Voluntary Contractions (MVC) of 4 right arm muscles (RAM), 5 right leg muscles (RLM), and 2 body trunk muscles were measured with an isometric dynamometer, respectively. Muscle masses (MM) of right arm and leg and body trunk were determined by dual energy X-ray absorptiometry, respectively. The maximum cross sectional area (CSAmax) of right m. quadriceps femoris was measured by magnetic resonance imaging. Elbow flexion MVC in males and all MVC of RLM except knee flexion in both males and females were decreased (p<0.05), but elbow extension MVC in females was increased (p<0.05), while all of other MVC only tended to decrease. However, the decrements in leg MVC were not correlated to the leg MM, and also the decrement in knee extension was not correlated to the CSAmax of m. quadriceps. The reduction of MVC of antigravity muscles might be caused not only by a decrease in MM but also by other factors. The greater decrements of leg MVC during BR were the higher initial level in males, but the inverse was observed in females. However, this discrepancy between males and females cannot be explained in the present study.

Adolescent↗

PubMed1997

Effects of 20 days horizontal bed rest on maintaining upright standing posture in young persons.

The effects of 20 days horizontal bed rest (BR) on postural reflex were studied by measuring fluctuation of center of gravity in the body during two legs or one leg upright standing in 10 young volunteers. The fluctuation was decided as total moving distance of the center recorded during 60sec standing on a force plate. The stability was measured by the moved area. After BR, the moving distance increased during two legs standing with open eyes (p<0.05), but statistically unchanged with closed eyes. The moving area decreased during right one-leg standing with closed eyes (p<0.05), but unchanged during left one-leg standing. Despite with open eyes the increased distance suggested that postural reflexes to maintain upright position were probably decreased by increased unsuitable feedback informations from the visual receptor deconditioning during BR. The decreased area during right one-leg standing with closed eyes also suggested that the declined standing posture reflex was probably related to more rapidly lowered functions for maintaining standing position in the dominating leg than in the other.

Adult↗

PubMed1997

Effects of 20 days horizontal bed rest on kinesthesia during knee flexion and two-point discrimination in skin of young subjects.

Investigating the effect of 20 days bed rest (BR) on kinesthesia and two-point discrimination, 10 young volunteers participated in this study as subjects. Angle position sensation of right knee was measured in the prone position during flexion and extension monitored by a goniometer after two-point discrimination in skin was determined on the same lower leg. Flexed constant error was unchanged but directional constant error and absolute error were increased after BR (p<0.05). Two-point discrimination was unchanged after BR, which brought about a decline of the orientation of moving the joint indicated as over shooting of the angle during knee flexion, while it did not affect superficial sensation observed by two-point discrimination. Probably, an adjustment of deep sensation to the knee joint is lowered by the reduction in kinesthesia as well as the sensory disturbance during BR, which is independent on information from superficial sensation.

Adult↗

PubMed1997

[High-dose methylprednisolone pulse therapy for respiratory failure after open heart surgery].

After open-heart surgery, we sometime experience a patient whose respiratory function worsens extremely, though a heart function is improved. We experienced four such cases and treated with high-dose methylprednisolone. Then, we recognized that the respiratory function was improved at all cases. However, one case deteriorated again regarding the respiratory function, as a start of the treatment was delayed. There is a possibility that host resistance to infection is decreased by administration of corticosteroids. Therefore, we hesitate to treat with corticosteroids. Concerning respiratory failure after open heart surgery, however, we think that a respiratory function of a patient is improved if high-dose methylprednisolone pulse therapy is started in early stage.

Aged↗

PubMed1997

[A case of successful surgical treatment for active endocarditis 2 days after the onset of cerebral infarction].

We performed double valve replacement for a patient with active endocarditis 2 days after the onset of cerebral infarction because of intractable cardiac failure. The use of heparin and the hypotension brought by cardiopulmonary bypass can lead exacerbation of the cerebral symptoms after open heart surgery which is performed during acute phase of cerebral infarction. Perfusion pressure was maintained over 70 mmHg during cardiopulmonary bypass and activated clotting time was kept about 400 seconds to prevent aggravation of cerebral complications in this case. The patients recovered from surgery uneventfully. We described a case who was received double valve replacement 2 days after the onset of cerebral infarction successfully.

Aortic Valve↗

PubMed1997

Persistent sciatic artery aneurysm with ruptured internal iliac artery aneurysm.

A case of aneurysm of persistent sciatic artery with ruptured aneurysm of the internal iliac artery is reported. A 62-year-old man was admitted to our hospital in emergency because of abdominal severe pain. Abdominal CT and angiography showed aneurysm of the infrarenal aortic aorta and left internal iliac artery and left persistent sciatic artery. The persistent sciatic artery aneurysm was coursed down the left thigh. Left superficial femoral artery was supplying blood to the popliteal artery as normal connection. Emergency operation was performed. The left internal iliac aneurysm was ruptured to a retroperitoneal space. The aneurysm was replaced by a Y-shaped dacron double velour graft from the infrarenal abdominal aorta to right common iliac and left external iliac arteries, which was followed by a ligation at the origin of left persistent sciatic aneurysm. The pulsation of the left lower extremity was good and additional bypass procedure to the popliteal artery was not performed. The post-operative course of the patient was excellent and post-operative angiography showed normal anatomy of the left lower extremity. Optimal management of ruptured abdominal aneurysm thus requires not only an emergency operation but detailed observation of preoperative CT and angiography in order to scrutinize the associated vascular anomalies.

Aneurysm↗

PubMed1997

[Assessment of quality of life in long-term results of patients over 75 years old after emergent cardiovascular surgery].

Long-term results in QOL of patients over 75 years old after emergent cardiovascular surgery were examined. From January 1991 to June 1996, 46 patients underwent cardiovascular surgery. 22 patients who had elective surgery (elective group) and 15 patients who had emergency surgery (emergency group) tolerated with the operation: Two-year survival rate after surgery was 80.7% in the elective group and 78% in the emergency group, and relative survival rate was 0.89 in the elective group and 0.86 in the emergency group. As regards to the ability to live independently, 89% of elective group and 75% of emergency group showed good improvement, and there was no significant difference between two groups. The rate of patients who did not feel anxiety for disease at all was 61.1% in the elective group and 41.7% in the emergency group. The relationship between the patient and his family was good in both groups. For physical condition, the emergency group was superior to the elective group with no significant difference. Although QOL was relatively good after emergency surgery, some items were inferior compared with elective surgery. To improve the long-term results, elective surgery is required to avoid emergency surgery.

Age Factors↗

PubMed1996

The activation of K-ras gene at an early stage of lung tumorigenesis in mice.

To clarify the exact timing of K-ras gene mutational activation in lung tumorigenesis of mice, we applied a sensitive mutant allele specific amplification (MASA) method to pulmonary DNA from urethane-treated mice. The activation of K-ras gene with 61st codon AT mutation was detected in the lungs of mice at day 14 but not day 7 after urethane treatment by MASA. The mutation of MASA products was also checked by XbaI restriction fragment length polymorphism analysis and DNA sequencing. These data suggest that the mutation of K-ras gene in the lungs of mice treated with urethane occurred at the early stage of lung tumorigenesis.

Animals↗

PubMed1996

Involvement of rho p21 in cyclic strain-induced tyrosine phosphorylation of focal adhesion kinase (pp125FAK), morphological changes and migration of endothelial cells.

The molecular mechanisms by which endothelial cells sense and respond to physical forces remain to be elucidated. Recently we reported that cyclic strain-induced morphological change and migration of EC were regulated by the tyrosine phosphorylation of focal adhesion kinase (pp125FAK) and paxillin. The aim of the present study was to clarify the role of the small GTP-binding protein rho p21 in EC exposed to cyclic strain. Bovine aortic endothelial cells (EC) were subjected to 10% average strain at 60 cycle/min. Clostridium botulinum C3 transferase (C3) was used as a specific inhibitor of rho p21. Preincubation of EC with C3 inhibited ADP-ribosylation of rho (94%) and inhibited the morphological change, reorganization of actin filaments, and migration induced by cyclic strain. Moreover, C3 inhibited the cyclic strain-induced tyrosine phosphorylation of pp125FAK and paxillin. These results demonstrate that rho downregulates the tyrosine phosphorylation of pp125FAK and paxillin and can modulate the morphological changes and migration induced by cyclic strain.

ADP Ribose Transferases↗

PubMed1996

Suppressive effects of retinoids, carotenoids and antioxidant vitamins on heterocyclic amine-induced umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002).

Effects of retinoids, carotenoids and antioxidant vitamins were studied by mutagen-induced umu C gene expression system in Salmonella typhimurium (TA 1535/pSK 1002). Retinol (vitamin A), retinol acetate and retinoic acid showed remarkable inhibitory activities, whereas retinol palmitate exhibited significant but weak activity for umu C gene expression in tester bacteria induced by 3-amino-3,4-dimethyl-5H-pyrido[4.3-b]indol (Trp-P-1) in the presence of hepatic metabolizing enzymes (S9 mixture). Carotenoids having provitamin A activity (beta-carotene and canthaxanthin) exhibited moderate suppressive effects on the same experimental system. The ranks of suppressive activities were retinol > retinol acetate > retinoic acid > canthaxanthin > beta-carotene > retinol palmitate and their doses for inhibition by 50% (ID50) were estimated to be 1.2 x 10(-7), 3.0 x 10(-7), 5.4 x 10(-7), 1.5 x 10(-6), 4.0 x 10(-5) and 6.0 x 10(-5) M, respectively. However, they did not cause significant inhibition on umu C gene expression induced by direct-acting mutagen (adriamycin or mitomycin C) in the absence of S9 mixture. Inhibition of umu gene expression appears to be due to inhibition of P450-mediated metabolic activation of the heterocyclic amine Trp-P-1. Ascorbic acid (vitamin C) showed weak but significant suppressive activity at high-dose concentrations (3 x 10(-6) - 10(-4)M). However, alpha-tocopherol did not exhibit significant suppression at all dose concentrations. The significance of the experimental results is discussed from the viewpoint of the chemoprevention against genotoxicity associated with carcinogenesis.

Animals↗

PubMed1996

Identification of antimutagenic substances in an extract of edible red alga, Porphyra tenera (Asakusa-nori)

Recently, a relatively strong antimutagenic activity has been detected in the extract of Porphyra tenera (Asakusa-nori in Japanese) which showed a suppressive effect on mutagen-induced umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002 (Okai et al. (1994) Cancer Lett., 87, 25-32). In the present paper, we analyzed the active principles for the antimutagenic activity in an extract of Porphyra tenera and detected three color spots on a silica gel TLC plate which indicated very similar Rf values and absorbance spectra of standard pigments such as beta-carotene, chlorophyll a and lutein. The seaweed pigments recovered from preparative silica gel TLC corresponding to beta-carotene, chlorophyll a and lutein exhibited significant suppressive activities against mutagen-induced umu C gene expression and combined treatment with these pigments showed an additive effect compared with single treatment with each pigment. Furthermore, the standard pigments prepared from other biological sources also exhibited similar anti-mutagenic activities. The significance of this finding is discussed from the protective role of seaweed pigments against mutagenesis probably associated with carcinogenesis.

Antimutagenic Agents↗

PubMed1996

Hepatocyte growth factor induces transglutaminase activity that negatively regulates the growth signal in primary cultured hepatocytes.

Transglutaminase (TGase) activity increased 2.5-fold at 6 h after treatment of rat hepatocytes with 117 nM hepatocyte growth factor (HGF). In the same manner, putrescine incorporation into proteins of cells occurred in HGF-treated cells but did not in those pretreated with monodansylcadaverine (MDC), a TGase inhibitor, even in the presence of HGF. These results suggest that HGF-induced TGase was active and catalyzed some cross-linkage reaction. Cycloheximide completely blocked the increase in TGase activity induced by HGF, suggesting that HGF stimulated de novo synthesis of TGase within 6 h. Both [35S]methionine incorporation and Northern blotting analyses supported this possibility. Pretreatment of cells with MDC additionally increased HGF-induced DNA synthesis and the ratio of cells in S-phase. Similarly, TGase antisense oligonucleotide inhibited de novo synthesis of TGase, resulting in increase in the ratio of S-phase cells in the presence of HGF. Analyses of cross-linking of HGF to the receptor indicated that the antisense oligonucleotide inhibited the downregulation of HGF receptor subsequent to HGF-addition. These results provide the first evidence for inducibility of de novo synthesis of TGase by HGF and suggest that TGase negatively regulates the growth signal of HGF through the downregulation of receptor.

Animals↗

PubMed1996

Functional organization of mammalian hexokinase II. Retention of catalytic and regulatory functions in both the NH2- and COOH-terminal halves.

The mammalian hexokinase (HK) family includes three closely related 100-kDa isoforms (HKI-III) that are thought to have arisen from a common 50-kDa precursor by gene duplication and tandem ligation. Previous studies of HKI indicated that a glucose 6-phosphate (Glu-6-P)-regulated catalytic site resides in the COOH-terminal half of the molecule and that the NH2-terminal half contains only a Glu-6-P binding site. In contrast, we now show that proteins representing both halves of human and rat HKII have catalytic activity and that each is inhibited by Glu-6-P. The intact enzyme and the NH2- and COOH-terminal halves of the enzyme each increase glucose utilization when expressed in Xenopus oocytes. Mutations corresponding to either Asp-209 or Asp-657 in the intact enzyme completely inactivate the NH2- and COOH-terminal half enzymes, respectively. Mutation of either of these sites results in a 50% reduction of activity in the 100-kDa enzyme. Mutation of both sites results in a complete loss of activity. This suggests that each half of the HKII molecule retains catalytic activity within the 100-kDa protein. These observations indicate that HKI and HKII are functionally distinct and have evolved differently.

Animals↗